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Re: how to set entry cache



--On Thursday, April 28, 2005 11:13 AM +0800 çåå <luozhijian@huawei.com> wrote:

but "how to work out what works best for your system"
if I have import 10k entry data to bdb,then
dn2id.bdb+id2entry.bdb=500MB,Can I think a entry = 500/10000 MB??

"idlcachesize Specify the size of the in-memory index cache, in index
slots."what is index slots? if I have 10k entry,and config
index   objectClass     eq
index   cn,sn   pres,eq,sub

then the max index slots is 10k*3 or 10k or 3?and how to work out how
large is one index slots?

"cachesize" specifies how many entries to cache in system memory, and it caches the entries that are most frequently accessed. The amount of entries that can be cached is going to be limited by your available memory. The size of the *.bdb file has nothing to do with how large an entry cache you should set. As I said, you are going to have to experiment.

"idlcachesize" specifies how many result sets from completed queries to cache in system memory, and it caches the most frequently returned result sets. The amount of result sets that can be cached is going to be limited by your available memory. As I said, you are going to have to experiment.

A general rule of thumb is to set idlcachesize to 3 * the size of the cachesize, but that is not also sufficient.

Basically, these two settings are things *you* have to experiment with to find the correct settings for for your systems, because they are limited in scope by the amount of available memory you have. As far as cachesize is concerned, being able to cache your entire DB in memory will always be a performance boost, but only if you have enough memory available to do that. The larger the idlcachesize you can support is probably the better as well.

--Quanah


--
Quanah Gibson-Mount
Principal Software Developer
ITSS/Shared Services
Stanford University
GnuPG Public Key: http://www.stanford.edu/~quanah/pgp.html

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